P1099
P1099Mass air flow ahead of throttle valve (MAF2) implausible (too low)
Diagnostic conditions
- Battery voltage between 10 V and 16 V
- Engine running
- No electrical MAF2 sensor fault
- No throttle valve adjusting unit fault
- No ambient pressure sensor fault
- No intake air temperature sensor fault
- No speed sender fault
Possible fault cause
- Hot-film mass air flow sensor 1 faulty (setpoint voltage with stopped engine and ignition on = 0.9 to 1.1 V)--> see Actual values, Filter [[DME mass air flow]], >>Mass air flow 1 (sensor)<<
- Clogged air cleaner
- Leakage between MAF2 sensor and throttle valve adjusting unit
Affected terminals
-
Diagnosis/fault finding
Hint:
- For this fault code, the intake system between the hot-film mass air flow sensor and the throttle valve is monitored.
- A mass air flow is calculated from the signals from the throttle valve potentiometer, engine speed sender, intake air temperature sensor and ambient pressure sensor and compared with that measured via MAF2 sensor.
